Cosmology in generalized Proca theories

Antonio De Felice, Lavinia Heisenberg, Ryotaro Kase, Shinji Mukohyama, Shinji Tsujikawa, Ying Li Zhang

Research output: Contribution to journalArticle

76 Citations (Scopus)

Abstract

We consider a massive vector field with derivative interactions that propagates only the 3 desired polarizations (besides two tensor polarizations from gravity) with secondorder equations of motion in curved space-time. The cosmological implications of such generalized Proca theories are investigated for both the background and the linear perturbation by taking into account the Lagrangian up to quintic order. In the presence of a matter fluid with a temporal component of the vector field, we derive the background equations of motion and show the existence of de Sitter solutions relevant to the late-time cosmic acceleration. We also obtain conditions for the absence of ghosts and Laplacian instabilities of tensor, vector, and scalar perturbations in the small-scale limit. Our results are applied to concrete examples of the general functions in the theory, which encompass vector Galileons as a specific case. In such examples, we show that the de Sitter fixed point is always a stable attractor and study viable parameter spaces in which the no-ghost and stability conditions are satisfied during the cosmic expansion history.

Original languageEnglish
Article number48
JournalJournal of Cosmology and Astroparticle Physics
Volume2016
Issue number6
DOIs
Publication statusPublished - 2016 Jun 28

Keywords

  • Cosmological perturbation theory
  • Dark energy theory
  • Modified gravity

ASJC Scopus subject areas

  • Astronomy and Astrophysics

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